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The present communication is an attempt to explore the synergistic effect of two indigenous phosphate solubilizing bacteria (PSB) (Pseudomonas fluorescens BAM-4 and Burkholderia cepacia BAM-12) and arbuscular mycorrhizal (AM) fungus, Glomus etunicatum on growth, yield and nutrient uptake of wheat plants grown in nutrient deficient soils in pots amended with tricalcium phosphate (TCP). A significant increase in growth, yield and nutrient uptake of wheat plants was noticed and both strains of PSB interacted positively with AM fungus towards all growth parameters studied. A remarkable enhancement of seed yield was recorded notably by 92.8% and an increase in percent root colonization of AM and PSB population in soil was also recorded with time.

In the present investigation, the preparation and characterization of a curcumin nanoemulsion with milk protein (sodium caseinate) and its incorporation into ice cream were undertaken. Among the different combinations, the most stable formulation was observed using milk fat (8%), medium chain triglycerides (2%), curcumin (0.24%) and sodium caseinate (6%) with a mean particle size of 333.8 ± 7.18 nm, a zeta potential of -44.1 ± 0.72 mV and an encapsulation efficiency of 96.9 ± 0.28%. The effect of different processing conditions (heating, pH and ionic strength) on the particle size distribution and zeta potential of the nanoemulsion was evaluated. During heat treatment, the particle size of the nanoemulsion was increased from 333.8 ± 7.18 to 351.1 ± 4.04 nm. The nanoemulsion was destabilized at pH 4.6 and the particle size increased above and below pH 5.0. However, there was a slight increase in the particle size with a change in the ionic concentration. The release kinetics data suggested that in simulated gastro-intestinal digestion, the nanoemulsion was stable against pepsin digestion (a 5.25% release of curcumin), while pancreatic action led to a 16.12% release of curcumin from the nanoemulsion. Finally, our formulation was successfully incorporated into ice cream and the sensory attributes were evaluated. No significant difference was observed in the scores of the sensory attributes between the control and ice cream prepared with a curcumin nanoemulsion. Moreover, the encapsulation efficiency of the curcumin incorporated into the ice cream was 93.7%, which indicates that it can withstand the processing conditions. The findings suggest that ice cream is a suitable dairy product for the delivery of lipophilic bioactive components (curcumin) which can be used for therapeutic purposes.

Molecular characterization of rhizobacterial isolate RM-3, based on sequencing of a partial 1,313-bp fragment of 16S rDNA amplicon, validated the strain as Pseudomonas aeruginosa. The strain showed significant growth inhibition of different phytopathogenic fungi in dual plate and liquid culture assays. Maximum growth inhibition was found in case of Macrophomina phaseolina in plate assay (68%), whereas it was 93% in Dreschlera graminae in dual liquid assay. Microscopic studies (light and scanning electron) showed morphological abnormalities such as perforation, fragmentation, swelling, shriveling and lysis of hyphae of pathogenic fungi. The strain also exhibited production of siderophore and hydrogen cyanide (HCN) on chrome azurol S and King's B media, respectively. Besides, this strain also produced extracellular chitinase enzyme and an important antibiotic, phenazine. Seed bacterization with RM-3 showed a significant (P < 0.05) increase in seed germination, shoot length, shoot fresh and dry weight, root length, root fresh and dry weight and leaf area. It was also able to colonize the rhizosphere of plants and reduced percent disease incidence in M. phaseolina-infested soil by 83%. Yield parameters such as pods, number of seeds and grain yield per plant also enhanced significantly (P < 0.05) in comparison to control. Thus, the secondary metabolites producing Pseudomonas aeruginosa strain RM-3 exhibited innate potential of plant growth promotion and biocontrol potential in vitro and in vivo.

Available phosphorus is limiting in most of cultivable soils in several parts of India, including Rajasthan. The beneficial effects of rhizosphere microorganisms such as phosphate solubilizing bacteria (PSB) have been found to increase in the presence of mycorrhizal symbiosis. In view of this, the synergistic effect of an arbuscular mycorrhizal fungus (AMF), Glomus etunicatum and an indigenous PSB strain, Burkholderia cepacia BAM‐6 was studied on wheat plants grown in pots containing soil with low available P to see their potential to be used as bio‐inoculants in semi‐arid regions. The dual inoculation (AMF + PSB) augmented all growth and yield parameters studied in comparison to the individual inoculations with AMF and PSB. Crop yield and N concentration were enhanced >50 and 90%, respectively, following the dual inoculation, and percent root colonization by AMF and rhizosphere population of PSB were also found to increase with time in soil. This investigation reveals that the PSB strain B. cepacia BAM‐6 interacted synergistically with AMF in promoting plant growth and nutrient uptake of wheat plants, therefore show great promise to be used as bio‐fertilizer for wheat crop grown in arid to semi arid regions.

Pseudomonas fluorescens BAM-4, Burkholderia cepacia BAM-6 and B. cepacia BAM-12 isolated from the rhizosphere of moong bean (Vigna radiata L.) showed significant growth-inhibitory activity against a range of phytopathogenic fungi. Light and scanning electron microscopic (SEM) studies showed morphological abnormalities such as fragmentation, swelling, perforation and lysis of hyphae of pathogens by Pseudomonas and Burkholderia. Two of the strains (BAM-4 and BAM-6) produced siderophore in CAS agar plates, whereas all three strains produced chitinase. Bacterization of seeds of moong bean with pseudomonads has been reported as a potential method for enhancing plant growth and yield, and for providing protection against Macrophomina phaseolina. Seed bacterization with these plant growth-promoting rhizobacteria (PGPR) showed a significant increase in seed germination, shoot length, shoot fresh and dry weight, root length, root fresh and dry weight, leaf area and rhizosphere colonization. Yield parameters such as pods, number of seeds, and grain yield per plant also enhanced significantly in comparison to control. The disease suppression and plant growth enhancement along with the positive rhizosphere colonization by these strains indicate their possible use as PGPR/ biocontrol agents against charcoal rot.

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